‘Wear a mask’: Doctor demonstrates how prolonged mask-wearing does not lead to carbon dioxide retention

A doctor in Australia shared a video on Twitter aiming to debunk concerns that wearing a mask for a prolonged period of time could cause harm, including the possibility of retaining or breathing in more carbon dioxide.

Dr. Tanya Selak, an anesthetist based in New South Wales, posted a video July 15 after having worn a mask for six hours on the job with the caption: “Wearing a mask does not cause carbon dioxide retention.”

“So there’s some concern that if you wear a mask, your CO2 levels will rise and you’ll become unconscious,” Selak states in the video. “We started at 7 o’clock this morning. It’s almost 1 (p.m.). I’ve had this mask on the whole day, and it’s just a normal surgical mask.”

Selak then tests her carbon dioxide levels as she breathes and speaks to the camera. A monitor shows the CO2 levels rise and fall “well within the normal range.”

“As you’ll see, just by having had this mask on for six hours, my CO2 levels are well within the normal range and I feel great,” she says in the video. “So, wear a mask. It’s fine.”

A screengrab shows Tanya Selak demonstrating how her carbon dioxide levels rise and fall normally while wearing a mask. (Photo credit: Tanya Selak / Twitter)

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Vanderbilt University also aimed to calm concerns related to prolonged mask-wearing.

“Prolonged use of any face mask, including the N95 respirator, has not been shown to cause carbon dioxide toxicity or lack of adequate oxygen in healthy people,” the university states on its website. “For some persons with severe chronic lung disease, wearing a mask may make breathing more difficult, but not because of CO2 retention.”

Vanderbilt also points out that health care workers routinely wear masks for prolonged periods during surgery or other routine care, and “adverse effects from this practice have not been reported.”

As of July 20, the U.S. leads the world with more than 3.7 million confirmed cases and 140,500 deaths, according to data compiled by Johns Hopkins University.

The Centers for Disease Control and Prevention has called on Americans to wear masks in public to help slow the spread of COVID-19, citing evidence that cloth face coverings help prevent those infected from transmitting the virus to others.

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A widely-cited coronavirus pandemic model used by the White House showed that if almost everyone wears a mask in public over the next few months, tens of thousands of lives could be saved in the U.S.

“We are not defenseless against COVID-19,” said CDC Director Dr. Robert R. Redfield. “Cloth face coverings are one of the most powerful weapons we have to slow and stop the spread of the virus – particularly when used universally within a community setting. All Americans have a responsibility to protect themselves, their families, and their communities.”

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This story was reported from Cincinnati.